磁致取向对镍粉填充丙烯酸酯复合涂层导电与屏蔽性能的影响

Influence of magnetic-field-induced-alignment on the conductivity and electromagnetic shielding effectiveness of Ni/polyacrylate coatings

  • 摘要: 采用磁场控制导电镍颗粒在丙烯酸酯乳液中的排列,制备了镍粉/聚丙烯酸酯复合涂层.采用扫描电镜对施加磁场前后涂层的微观形貌进行了表征,研究了磁致取向对复合涂层电导率和屏蔽效能的影响,并结合动力学模型探讨了影响磁致取向时间的因素.结果表明,磁致取向可以在涂层中形成"纤维束"状的微观组织,提高其电导率,使复合涂层导电渗阀值从5.6%降至3.0%(体积分数).经磁致取向后涂层的屏蔽效能曲线变化均匀,电磁屏蔽效能得到优化;磁致取向时间可以通过改变磁场强度和体系黏度来进行控制.

     

    Abstract: Ni/polyacrylate conductive coatings were prepared by utilizing magnetic field to control the alignment of nickel particles in acrylic emulsion. Their surface morphologies with and without the application of magnetic field were analyzed by SEM. The effect of magnetic field on the conductivity and shielding effectiveness of the coatings was studied. In combination with a dynamic model the influencing factors on the time of magnetic-field-induced-alignment (MFIA) was discussed. The results reveal that MFIA helps to generate a yarn-shaped microstructure in the coatings, which improves their conductivity. The percolation threshold of the resulting coatings decreases from 5,6% to 3.0% in volume fraction. Compared to the unaligned, the shielding effectiveness curve presents an even distribution after MFIA, and the electromagnetic shielding effectiveness is optimized. Alignment time can be controlled by changing the system viscosity and the applied magnetic intensity.

     

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